6-7% of all bitcoins in the hands of unknown criminals is very, very bad for bitcoin and will have repercussions, both short and long term, that we can't even begin to fathom at this point.
Exchanges worldwide have already been served with subpoenas. There is ample evidence that large scale blockchain mapping efforts have been underway for quite some time now. Some groups already have evidence to at least partially substantiate Mt.Gox's "malleability" hacking claims.
Hopefully at least some of these coins will be traced/seized/recovered. It's difficult to completely obfuscate 6-7% of all bitcoins over several years without slipping up somewhere.
... or maybe we could just peg them to Dogecoin at 1:1.
But seriously - this could be a difficult test for the 'fungibility' of bitcoin. If the coins are somehow tracked, should they really be considered untainted or could this lead to legitimization of the black- or redlisting that's been previously proposed?
once they hit a big mixer like satoshi dice or btc-e,it would be more or less impossible to prove they were anybodys from gox
also changing the core principals of bitcoin is wrong imo ,the coins can be split down to 0.000000001
which leaves 21 billion satoshis ? theres no need for everyone to keep thinking of full coins as they become
harder to mine and more valuable